I would like to know exactly what text causes the GMail pop-up dialog box that warns that you may have forgotten to attach files to an e-mail.
I have visited a lot of webpages describing the feature, ...

There is an email I need to send but attachments can't be base64 or my email gets rejected.
I checked within Gmail settings to see if there was some sort of option to change that but found nothing.
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Today my Gmail login activity has shown me that I was twice logged in from a strange place and additionally, I found in my trash label two emails from (unknown sender) with subject 'Attachment' with ...